This invention relates to the field of counting stacked signatures from the end of a printing press prior to bundling. More particularly the invention relates to an apparatus used in conjunction with a detector and a counter for such signatures which provides an indicium to the operator of a stacking machine as to when a predetermined count of signatures has ocurred.
Signature stackers are used to convey paper signatures from the fly end of a printing press to a receiving station where they are stacked, and later compressed and bundled for shipment. U.S. Pat. No. 4,463,940 describes such a stacker which includes an in-feed conveyor containing a conveyor jogger which initially carries a stream of shingled signatures from the press. The signatures are then conveyed to a pair of crusher rollers to remove air therefrom and then to a compression zone consisting of a pair of floating conveyor timing belts and a series of compression rollers in which the signatures are conveyed between the timing belts in an upward arch. Leaving the compression zone the stream of signatures having upward thrust are kicked, stopped, simultaneously engaged and jogged in a vertical stacking mode at a receiving station. Thereafter, the signatures are removed to a bundling station where they are compressed and bundled.
In most instances it is necessary to obtain a count of the stacked signatures prior to bundling. This can be achieved manually or by using a detector which detects the heads of each signature and a counter which determines the signature count. However, even using these devices the operator must still find that signature which corresponds to the predetermined count. Such target signature is located at the position of the detector which may be located at any position along the signature stream so that the problem becomes one of accurate determination and selection.
The present invention, on the other hand, provides an apparatus located in the in-feed conveyor of a stacker and used in conjunction with a detector-counter which provides an indicium to the operator at the receiving station as to when the predetermined count is reached. The indicium consists of a tab formed by an outwardly moved signature in the stream corresponding to the count and the apparatus of the invention accomplishes this function.